The prior art for this invention can be found in U.S. Class 403, Subclass 163, which generally covers connecting means, such as rod end connectors.
An important prior art reference is U.S. Pat. No. 3,832,074 issued on Aug. 27, 1974, to David C. Dehar for "linkage quick-connect device", as well as to U.S. Pat. No. 3,231,300 issued on Jan. 25, 1966, to W. N. Moroney for "connecting means". These patents are exemplary of a number of patents showing devices for connecting an operating rod to a lever or other workpiece. In certain of these patents, such as Moroney U.S. Pat. No. 3,231,300, the inventors have made provisions for a quick coupling action involving the fitting of a bent end of the rod into an axially disposed bore as well as having means for snap fitting the rod into a recess in the head of the connecting device. These do not provide for any axial adjustment of the rod. The Dehar U.S. Pat. No. 3,832,074 was an attempt to provide a connecting means which allowed for adjustment of the fastening device relative to the axial positioning along the coupling rod. The Dehar device taught the use of a threaded rod where the normal threads have a 60.degree. included angle between the oppositely facing faces of each thread, thereby providing a ramp angle of 30.degree.. When a 30.degree. ramp angle is loaded axially, the axial forces tend to cause mating surfaces to slip. This is further magnified when the thread form, as taught by Dehar U.S. Pat. No. 3,832,074, includes the helix angle of the thread. In loading the link rod, a slight cocking action between the link rod and the fastening device takes place. In fact, there are instances of where the link rod or elongated member actually becomes displaced relative to the fastening device.